I've been out of xwing for awhile and want to buy some scum and villainy. I've heard great things about two IG88 squads so I am debating between buying two of those or another firespray and most wanted for this list:

Mandalorian Merc: VI,HLC, Gunner

Boba Fett: VI,HLC,Gunner

vs.

IG88A and B with PTL, FCS, Mangler, Ion Cannon, title, Autothrusters

Igs by a long shot (though sensors >>>>>>>>>>>>>>>>> fcs or ion cannon)

The firesprays lack mobility and one of the best crew released. The k4 is ******* bonkers and it makes even cards such as expert handling (hint hint) worth using

I don't agree entirely with Fickle on aggressors. Both FCS & sensors are great, maybe sensors is better overall for flexibility, but FCS is very strong against high hull targets (and heavy b-wing lists can be a real problem for dual aggressors).

I agree K4 is a good new crew, but not so much for Boba. Expert handling is great, but there are other choices too.

Anyway, as to the OP's list, I personally don't see the point of running HLC + gunner. I'd drop one or the other. In fact, I am a big fan of Boba carrying VI, gunner + engine upgrade. Its all he really needs. As for a mando merc, Vet. Instincts is a waste of points. He's much happier with either predator for consistent damage, or as Fickle mentioned, expert handling + K4 security droid is a nice combo. Another option would be Eamon w/ Andrasta title and as many proximity mines as you can fit. He would like gunner too (and maybe K4) because he will be using his actions to drop the mines -- hopefully right on top of enemies due to his ability

For Aggressors, its usually PtL + FCS or Predator + advanced sensors (at least that's what most people seem to be doing). I think there are other possibilities, but those seem to work best. PtL + advanced sensors is a nice idea (using greens to clear stress when you move) until you s-loop/k-turn, and then you are alternating not using one or the other for pretty much the rest of the game...